1. Field of the Invention
The present invention relates to an ink-jet ink which improves the quality of a recorded image and has an excellent discharge stability, a method of manufacturing the same, and an ink jet recording method using the ink-jet ink.
2. Description of the Related Art
As computers have spread in recent years, ink jet printers have been widely used for recording on paper, film, cloth and the like not only in offices but also in homes. As ink jet recording inks, oil-soluble inks, water-based inks and solid inks are known. Of these inks, water-based inks are advantageous in view of ease of production and handling, smell, safety and so on. Thus, water-based inks are mainly used.
The reason why water-soluble inks in water-based inks are used is that a water-soluble ink has advantages of ease of production of the ink, superior preservation stability, good color hue and high color density. However, water-soluble dye has poor water resistance, so that bleeding is caused if recording is carried out with the ink on plain paper. As a result, problems that recording quality deteriorates remarkably and light resistance is poor arise.
Thus, for example, Japanese Patent Application Laid-Open (JP-A) No. 56-157468, JP-A No. 4-18468, JP-A No. 10-110126 and JP-A No. 10-195355 suggest water-based inks containing a pigment or a dispersed dye in order to solve the above-mentioned problems.
The water resistance of these water-based inks is improved to some extent. However, it is difficult to say that water resistance is sufficient, and the following problems arise: a dispersant of the pigment or the dispersed dye in the water-based ink has insufficient preservation stability, such that an ink jet opening is easily blocked with the water-based ink.
In contrast, JP-A No. 58-45272 discloses a method of including a dye in urethane polymer latex particles.
However, in this case, there are drawbacks in that color reproduction is not sufficient because of insufficient color tones and that, when a dye is included at a desirable density, dispersion stability or water tolerance of a dye-including polymer dispersed product is not necessarily satisfactory.
On the other hand, JP-A-10-279873 discloses a method in which an acrylic polymer and an oil-soluble dye are dissolved and dispersed in an organic solvent, and then the organic solvent is removed, and thereby colored polymer particulates are manufactured.
However, in this case, there is a drawback in that the quality of a recorded image, in particular, the quality of an image when the image is recorded onto a paper medium for a photographic image quality, or stability in continuous recording is not sufficient.
Further, Japanese Patent Application Publication (JP-B) No. 5-76977 discloses an ink composition in which an oil-soluble dye is dissolved and dispersed in an organic solvent whose solubility to water is small and whose specific gravity is close to water.
However, the phase solubility of the organic solvent which is defined in JP-B-5-76977 with the above-described oil-soluble dye is unsatisfactory in general. Accordingly, there are drawbacks in that a recording density is low, that, in some case, the dye deposits during the storage, and that a nozzle may be clogged.
An object of the present invention is to provide an ink-jet ink: which can record suitably as a water-based ink for writing, a water-based printing ink, an ink for information recording, or the like by a thermal, piezoelectric, electric field, or acoustic ink jet type; in which a dye does not deposit, in which, when printing or the like is carried out using a nozzle or the like, the distal end of the nozzle is not clogged and discharge stability is excellent; which has excellent handling ability, odor ability, safety; which has no paper dependence; which has excellent permeability at the time of recording; in which stains are not generated immediately after the recording; which has excellent color formation efficiency/color tone, water tolerance, light resistance; and in which an image having a high density and a high quality can be recorded. Further, an object of the present invention is to provide a method of manufacturing the ink-jet ink and an ink jet recording method using the ink-jet ink.
The object described above can be achieved by the following means:
A first aspect of the present invention is an ink-jet ink which comprises a dye dispersed product, an oil-soluble dye being dissolved in a high boiling point organic solvent which has a boiling point of 150xc2x0 C. or more and has a specific inductive capacity at 25xc2x0 C. of 3 to 12, said oil-soluble dye being emulsified and dispersed in a water-based medium, and said dye dispersed product being formed.
A second aspect of the present invention is a method of manufacturing an ink-jet ink, in which an oil-soluble dye is dissolved in a high boiling point organic solvent which has a boiling point of 150xc2x0 C. or more and has a specific inductive capacity at 25xc2x0 C. of 3 to 12, and said oil soluble dye being emulsified and dispersed at a pressure of 50 MPa (500 bar) or more using a high-pressure emulsifying and dispersing device.
A third aspect of the present invention is an ink jet recording method in which recording is carried out onto an image receiving material using an ink-jet ink which includes a dye dispersed product, an oil-soluble dye being dissolved in a high boiling point organic solvent which has a boiling point of 150xc2x0 C. or more and has a specific inductive capacity at 25xc2x0 C. of 3 to 12, the oil-soluble dye being emulsified and dispersed in a water-based medium, and the dye dispersed product being formed.